In addition to taking detailed pictures of celestial objects, Hubble's versatile and efficient Space Telescope Imaging Spectrograph (STIS) acts like a prism to separate light from the cosmos into its component colors. This provides a wavelength "fingerprint" of the object being observed, which tells us about its temperature, chemical composition, density and motion. Spectrographic observations also reveal changes in celestial objects as the universe evolves. STIS spans ultraviolet, visible and near-infrared wavelengths.

The
Great Black Hole Hunter

Astronomers use STIS to hunt for black holes. The light emitted by stars and gas orbiting the center of a galaxy appears redder when moving away from us (redshift), and bluer when coming toward us (blueshift). STIS looks for redshifted material on one side of the suspected black hole and blueshifted material on the other, indicating that this material is orbiting an object at very high speeds.

STIS can sample 500 points along a celestial object simultaneously. This means that many regions in a planet's atmosphere or many stars within a galaxy can be recorded in one exposure, vastly improving Hubble's speed and efficiency. Hubble also has a second spectrograph, the Cosmic Origins Spectrograph, which sees entirely in ultraviolet light. Together, the two spectrographs provide a wealth of data for astronomers to investigate.

STIS,
which was built by Ball Aerospace, was installed in the Hubble Space
Telescope during the 1997 Second
Servicing Mission.